marketing tags

What are marketing tags? Sorry to ask this, but I am really not familiar with it. Another question is what is tag management? I’ve googled it but still can’t understand it well, it’s just so technical for me. Can someone explain it to me in simple terms? Thanks!

Hi! Marketing Tags are the mediums for collecting data from a website. Data
that is collected from these tags power online marketing campaigns and
web analytic systems. A tag management system is designed to help manage the life cycle of e-marketing tags (sometimes referred to as tracking pixels or web beacons), which are used to integrate third-party software into digital properties. I hope this one helps.

I appreciate your help and I read an article saying “the same concept as what you are saying”. Anyway, one of my relatives also suggested this tag management software to answer my inquiry. I will try to read this as soon as I arrive at hour flat. TY